Mermish is a curious language that is specifically adapted for use underwater. When underwater it sounds much like English, or perhaps even like any other language (Harry Potter is the only one who is personally shown in the books to hear the merpeople); however, out of water the language changes to a screeching, harsh and raspy sound. Mermish also has a written form, as it was one of the seventy-two languages that Miranda Goshawk's Book of Spells was published in.

Mermish is a curious language that is specifically adapted for use underwater. When underwater it sounds much like English, or perhaps even like any other language (Harry Potter is the only one who is personally shown in the books to hear the merpeople); however, out of water the language changes to a screeching, harsh and raspy sound. Mermish also has a written form, as it was one of the seventy-two languages that Miranda Goshawk's Book of Spells was published in.